Adopting provisions - EGTRRA

1. What is the deadline for adding safe harbor provisions to an existing 401k Plan?

2. What is deadline for signing EGTRRA amendment for a restated plan (that previously signed EGTRRA amendment when the GUST restatement was done)

Client with existing 401k plan provides 401(k) safe harbor notice for the 2006 plan year to its employees on 12/1/05. Because document is volume submitter, brand new document must be executed which is done on 12/1/05.

However, client inadvertently did not sign egtrra on 12/1/05.

what is the deadline to sign egtrra amendment on a newly restated document to add 401k safe harbor provisions?

Does the fact that EGTRRA amendment not being signed have any affect on 401k safe harbor?